level n+level n=level max
it should equal level (n+1)

This is caused by adventureZ mod. If its not fixed by the next pack update, we will downgrade to the previous version which will fix this issue.

It also causes the over-leveled enchants from goblin traders to be unusable, hopefully that will also be fixed.

That also happens with normal tool/gear/weapon enchanting on all enchantments that have more than 1 level too
If I enchant a pick with Efficiency 1 the output will be a pick with Efficiency 5 at the xp cost of its level one enchantment.

no matter the item and the enchantment level on a book it will auto enchant to the maximum available always
that's very abuse-able but also bad since as it is mentioned above that ruins the over-enchantments goblin traders give you
and with the dark enchanter hiccup we had, almost everyone including me turned to villager farming for the books
when i noticed the bug it was already posted here so....